Mutable secure communication

Abstract

Secure communication provides data confidentiality, data integrity, and authentication. In one embodiment, encryption and signatures are used to construct a signcryption, which provides confidentiality and integrity. In one embodiment, an identifier and the output of a cryptographic function applied to a token are used to establish a secure channel. In one embodiment, a secure channel is mutated into a new secure channel using a renew message and a construct containing elements for establishing a secure channel.

What is claimed is: 
     
         1 . A method of signcryption, the method comprising:
 receiving a plaintext as input; and   buffering the plaintext to produce a block; and   producing a metadata for the block; and   producing a first digest for the metadata using a first signature; and   producing a second digest for the block using a second signature; and   producing a ciphertext by applying an encryption to the metadata and the first digest and the block and the second digest; and   outputting the ciphertext.   
     
     
         2 . The Method of  claim 1 , wherein the metadata contains the length of the block. 
     
     
         3 . The Method of  claim 1 , wherein the metadata contains a counter of the number of blocks produced. 
     
     
         4 . The Method of  claim 1 , wherein the metadata has a fixed length. 
     
     
         5 . The Method of  claim 1 , wherein at least one of first digest and second digest is not encrypted. 
     
     
         6 . The Method of  claim 1 , wherein at least one of first signature and second signature is keyless. 
     
     
         7 . The Method of  claim 1 , wherein the encryption has key replacement. 
     
     
         8 . The Method of  claim 1 , wherein the encryption is implemented as a stream. 
     
     
         9 . A method of establishing a secure channel, the method comprising:
 receiving input containing an identifier, a token, and a sequence representing a cryptographic function; and   writing the token into the channel; and   applying the cryptographic function to the token; and   writing the output of the cryptographic function into the channel; and   outputting a secure channel using the cryptographic function.   
     
     
         10 . The method of  claim 9 , wherein the cryptographic function is a signcryption. 
     
     
         11 . The method of  claim 9 , wherein at least one of the identifier and the token contain at least 64 bytes. 
     
     
         12 . The method of  claim 9 , further comprising sending a randomly selected first number on the secure channel and closing the channel if a second number equal to the first number is not sent in response. 
     
     
         13 . A method of mutating a secure channel, the method comprising:
 sending over a first secure channel a renew message from first party with a first storage to a second party with a second storage; and   generating using random values a construct containing elements used to establish the first secure channel; and   storing the construct on the second storage; and   sending the construct over the first secure channel from the second party to the first party; and   storing the construct on the first storage; and   replacing the first secure channel with a second secure channel using elements from the second construct.   
     
     
         14 . The method of  claim 13 , wherein the construct contains an identifier, a token, and a sequence representing a signcryption. 
     
     
         15 . The method of  claim 12 , wherein replacing the first secure channel with a second secure channel using elements from the second construct occurs immediately after storing the construct on the first storage. 
     
     
         16 . The method of  claim 12 , wherein the construct is associated with a counter that is incremented each time a secure channel is established. 
     
     
         17 . The method of  claim 12 , further comprising removing from first storage and second storage all constructs not used to establish the secure channel.